use std::{env, error::Error, fs};

pub fn run(config: Config) -> Result<(), Box<dyn Error>> {
    let contents = fs::read_to_string(config.file_path())?;
    let results = if config.ignore_case() {
        search_case_insensitive(config.query(), &contents)
    } else {
        search(config.query(), &contents)
    };

    for line in results {
        println!("{line}");
    }

    Ok(())
}

pub fn search_case_insensitive<'a>(query: &str, contents: &'a str) -> Vec<&'a str> {
    //let mut results: Vec<&str> = Vec::new();
    //for line in contents.lines() {
    //    if line.to_lowercase().contains(&query.to_lowercase()) {
    //        results.push(line);
    //    }
    //}
    //results
    contents
        .lines()
        .filter(|line| line.to_lowercase().contains(&query.to_lowercase()))
        .collect()
}
pub fn search<'a>(query: &str, contents: &'a str) -> Vec<&'a str> {
    //let mut results: Vec<&str> = Vec::new();
    //for line in contents.lines() {
    //    if line.contains(query) {
    //        results.push(line);
    //    }
    //}
    //results
    contents
        .lines()
        .filter(|line| line.contains(query))
        .collect()
}

pub struct Config {
    query: String,
    file_path: String,
    ignore_case: bool,
}

impl Config {
    //pub fn build(args: &[String]) -> Result<Config, &'static str> {//modified by c13
    pub fn build(mut args: impl Iterator<Item = String>) -> Result<Config, &'static str> {
        args.next();
        //if args.len() < 3 {
        //    return Err("not enough arguments");
        //}
        //let query = args[1].clone();
        //let file_path = args[2].clone();
        let query = match args.next() {
            Some(arg) => arg,
            None => return Err("Didn't get a query string"),
        };
        let file_path = match args.next() {
            Some(arg) => arg,
            None => return Err("Didn't get a file path"),
        };
        let ignore_case = env::var("IGNORE_CASE").is_ok();

        Ok(Config {
            query,
            file_path,
            ignore_case,
        })
    }

    pub fn query(&self) -> &str {
        &self.query
    }

    pub fn file_path(&self) -> &str {
        &self.file_path
    }

    pub fn ignore_case(&self) -> bool {
        self.ignore_case
    }
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn one_result() {
        let query = "duct";
        let contents = "Rust:\nsafe, fast, productive.\nPick three.";
        assert_eq!(vec!["safe, fast, productive."], search(query, contents));
    }

    #[test]
    fn case_sensitive() {
        let query = "Duct";
        let contents = "\
Rust:
safe, fast, productive.
Pick three.
Duct tape.";

        assert_eq!(vec!["Duct tape."], search(query, contents));
    }

    #[test]
    fn case_insensitive() {
        let query = "rUsT";
        let contents = "\
Rust:
safe, fast, productive.
Pick three.
Trust me.";

        assert_eq!(
            vec!["Rust:", "Trust me."],
            search_case_insensitive(query, contents)
        );
    }
}
